Safety device for diesel and internal-combustion engines



T. J. MOODY July 15, 1952 SAFETY DEVICE FOR DIESEL. AND INTERNAL-COMBUSTION ENGINES Filed May 26, 1947 Patented July 15, 1952 ,1 2,603,690 I SAFETY DEVICE FOR DIESEL AND INTER- NAL-COMBUSTION ENGINES Thomas J; Moody, Louisville, Ky., assignor to Robertshaw-Fulton Controls Company, a corporation of Delaware Application May 26, 1947; Serial No. 750,412 I 4 Claims. (Cl. 175320) This invention relatesto safety devices, and

more particularly to safety devices for internal combustion engines. Whilethe invention possesses particular utility in its application as a safety device to diesel engines, the invention is not restricted thereto, as will appear from the following disclosure, as the controlled element, for example, may be in the ignition circuit of an internal combustion engine of other than the diesel type, while other applications of the invention will be apparent to those skilled in the art.

Taking a diesel engine for purposes of exemplifying the invention, it has heretofore been proposed to provide such an engine with pressurecontrolled or thermostatically-controlled means or stopping the engine in the event of abnormally low oil pressure or abnormally high oil or water temperatures, but devices of this character have had the grave objection that they add materially to the complexity or .the bulk, or both, of the accessory installation. The present invention avoids the foregoing difficulty by utilizing means to close a switch upon the occurrence of abnormaly low lubricating oil pressure or abnormally high oil or jacket temperatures to energize a solenoid which cuts off the fuel supply, as by means of a valve'in the fuel line or bystoppage of the injection pump. In devices'of this character, as will be apparent, the switch in the solenoid circuit must be opened when the engine is started because otherwise'it would beimpossible to start the engine as long as the solenoid circuit is closed to hold the control element in position for'preventing operation of the engine. The operator, once the engine is in operation, is then supposed to close the manually operated switch in the solenoid circuit so as to condition the safety device for operation upon occurrence of the condition of danger, but if the operator forgets to close this switch, as after the oil pressure has come up to normal, the safety device is not in condition for operation and the subsequent lowering of the oil pressure or the occurrence of abnormally high oil or jacket temperatures will not energize the safety device to stop the engine.

It is the primary object of the present invention to provide a safety device of the type just characterized which is entirely safe because the operator is relieved of the responsibility of closing the switch through the solenoid after the engine is started.

A further object of the present invention is to provide a safety device of the character referred to wherein the circuit through the solenoid is automatically established when the engine is started.

A further object of this invention is to provide a safety device as characterized in which the circuit through the solenoid is closed only after a predetermined period of operation.

Another object of this invention is to provide a safety device as characterized which employs a time-delay switch that operates automatically when the engine is started.

Another object of this invention is to provide a safety device of the type characterized which employs a time-delay switch whose circuit is opened automatically when the circuit of the safety device is properly conditioned for normal operation.

A further object of this invention is to provide a safety device of the type characterized which may be used with solenoid valves or injection pump racks of the character now conventionally used in diesel engines and therefore with a minimum of alteration in the installations as now provided.

A further object of this invention is to provide a safety device of the type characterized which is certain in operation, and which also assures an adequate time delay before coming into operation so as to avoid. premature actuation of the safety device.

A further object of this invention is to provide a safety device of the type characterized which though called into action permits the engine to be started again and operated for a limited period of time, so that, for example, if a vehicle operated by an engine provided with such a safety device should be stopped in a hazardous position by the safety device coming into action the engine may be briefly operated to enable the vehicle moving out of such position.

Another object of this invention is to provide a device of the type characterized which is simple and compact in construction and inexpensive to install and maintain.

Other objects will appear as the description of theinvention proceeds.

. The invention is capable of receiving a variety of mechanical expressions, one of which is illustrated diagrammatically, so as to facilitate'an understanding of its principle of operation, on the accompanying drawing, but it is to be expressly understood that the drawing is for purposes of illustration. only, and is not to be construed as a definition of the limits of the invention, reference being had to the appended claims for that purpose.

Referring in detail to the drawing, a schematic view illustrates diagrammatically a circuit arrangement embodying the present invention.

As illustrated, I9 designates any suitable solenoid in circuit with battery II, although any other suitable electromagnetic device may be used in place of a, solenoid as will be apparent to those skilled in the art. A manually operable switch I2 is in circuit with the'solenoid and battery, and operatively connected with'the core or armature I3 of the solenoid isa member... I4 for controlling the operation ofthe engine and which may take a variety of forms, as a valve in the valve is closed or the rack operates a valve of the injection pump to close the same and discontinue the operation of the pump. In place of a fuel Valve or rack on the injection pump, the member to be controlled can equally well be a member, as a switch, in the ignition system of 'an engine. When a solenoid valve is used the valve may be any of the well-known solenoid valves now conventionally used in the fuel line of a diesel engine. When arack on theinjection pump is used the construction employed may be any of those now used for controlling the operation of the injection pump.

Connected at I5 to one of the leads I6 of the solenoid I9 is a conductor I7 leadingto the contact point I8 of a switch I9. Switch I9 is associated in any suitable way with means responsive to pressure, or to temperature, or to both, for closing the switch I9 when a dangerous condition arises, as an undue drop in the pressure of the oil, or an undue rise in temperature of the cooling water or the oil, etc. As shown, a pressure responsivemember 20, here shown as in the formof an expansible and contractible corrugated tubular metal container or bellows, has its interior connected with any suitable source of oil pressure, as the primary oil filter, so as to be responsive to the oil pressure developed by the oil pump. Bellows is connected to the switch I9 in any suitable way, as bya link diagrammatically indicated at 2|. switch I9, or a second switch connected into the circuit in parallel therewith is also adapted to be operated by a rise of temperature,- andto this end any suitable thermostatic bulb 22, which maybe subjected to the temperature of the water in the water jacket or any other suitable part of the water line or to the temperature of the oil, etc., is suitably connected, as by conduit 23, to an expansible and contractible corrugated tubular metal container or bellows 24 having a thrust element 25 which may engage and operate the switch I9 or a second switch element connected in parallel thereto.

Switch I9 is connected by conductor26 to a multiple switch operable by any suitable relay coil 21. As illustrated diagrammatically, three contacts 28, 29 and 36, respectively, are positioned for contact with elements 3|, 32'and 33 carried byarmature 34 and suitably insulated from each other. Element 33 is connected with As here shown, the

4 conductor 26 and contact 30 is connected by conductor 35 with a connection 36 in the circuit of the solenoid but on the battery side of the switch I2 opposite from the connection I5. Element 32 is connected with the coil 21 by lead 31, and also by conductor 38 with the contact element 39 of a time-delay switch composed of a bimetallic strip 40 and a heater coil 4 I. Bimetallic strip 40 is connected to the contact elements 28 and 29 by conductors 42 and 43. Heater coil 4I is connected through conductor 44 with element 3.I and through conductor 45 withthe negative terminal of the generator by conductor 46,

the positive terminal of said generator being connected to the conductors 42, 43 through conductor 41. Conductor 45 is also connected to the relay coil 21 through conductor 48. It is to be understood. that contact elements 3|, 32 and 33 move together-as a unitin response to operation of the armature 34 by: relay coil 21.

As indicated in the drawing, the connections to the generator circuit must be made at some point between the generator armature terminals and the generator cutout relay. The circuit through which the battery I I is normally charged is completed by a conductor 59. from the ,lefthand end of the solenoid II] to conductor 46 which is the negative side of the batteryll. The positive side of the battery II is connected to-the stationary contact 52- of the cut-out relay by conductor 5| to conductor 35. Since the re' maining connections .of the cut-out relay are conventional further description is deemed unnecessary. This connection is necessary inorder to prevent any potential being impressed on the circuit of the safety device until the engine is actually inoperation. As the generator cutout relay disconnects the generator from the battery circuit until. the generator potential is equal to or. greater than the battery potential, no potentialis impressed on the circuit above described until the engine is actually in operation.

When the engine is at rest the oil pressurein the bellows 2ll-is at zero and the bellows 20 is thus inits contracted position, holding the switch. I9 closed. Similarly. the temperature to which the bulb 22 is subjected is insufficient to expand the bellows 24..and the thrust. element 25 is out of contact with the switch, I9. Also, the relay coil 21 is deenergized and the armature thereof holds the contact elements 3 I, 32 and 33 in the position shown in the drawing, i. e., with contact 28 closing thecircuit through element 3| and contacts 29 and 39 out of engagement with the elements 32 and 33, respectively. In thisrelationship of theparts andassuming switch I2 is .open, the engine may be started because the circuit through the solenoid is open, and therefore the solenoid valve or the rack controlled valve is open to permit flow of fuel to the engine, because the battery II is disconnected from the'solenoid at the contact 3!] and the generator is disconnected from the solenoid at the contact 29. The circuit through the heater coil H is closed, however, at contact 28 for energization as soon as the generator comes into operation- When the engine is started the generator impresses a potential on the circuit of the heater coil, causing current to flow through conductor 41, contact 28, element 3|, conductor 44, heater coil M and conductor 45, but no current will flow through the relay because contact 39 in the circuit of the relay is out of contact with the bi-. metallic strip 49. After a lapse of a predetermined period of operation of the heater-coil 4'I,

say one minute, bimetallic strip 40 will have beensufliciently heated by the heaterf c'oil 4i Qffcause it] to bend into engagementwith the contactf39. This closure of the circuit at 39, lllfcauses current to'ilow through conductor 41, conductor 42, bimetallic strip 40, contact 39, conductor 38, conductor 31, relay coil "21 and conductor 48 The energizing of the relay coil Zloperates the-armature thereof tomove element 3| out of engagement with contact 28 and to move elements 32 and 33 respectively into engagement with the contacts 29 and. 3ll. The opening, of the circuit at 2B discontinues the operation of the heater coil, but current now flows through conductor 41, contact 29, conductor 31, relay coil 21 and conductor 48, thereby maintaining the circuit through the relay coil, while the solenoid ID has now been placed in circuit with the battery I I and the switch l9 through closure of the circuit at 29, 32 and at 30, 33. This is the normal running position for the device.

During the interval of time introduced by the time-delay switch 39, 40, if the engine operates normally, oil pressure has been sufficiently developed in the bellows 20 to open the circuit of the solenoid through switch l9, and thus the solenoid is out of operation to permit the normal running of the engine. In the event the oil pressure drops below a predetermined amount, or in the event the temperature to which the bulb 22 is subjected rises a predetermined amount, bellows 20 will contract to close switch I9 or bellows 24 will be expanded to close switch 19, thereby closing the circuit through the solenoid l0. Energization of the solenoid Ill or other electromagnetic control element eflfects the operation of the solenoid valve to stop the flow of fuel to the engine, or if the core of the solenoid is connected to a rack operatively connected to a valve on the pump, such valve is closed so as to stop the pump supplying fuel to the engine, or opens a switch in the ignition circuit, or otherwise efiects its control function. In any event, the engine is at once stopped upon the occurrence of the decrease in oil pressure or rise in temperature which should bring the safety device into operation.

It wil be observed that the operation of the safety device is thus not dependent upon the closure of the switch l2, because the circuit of the solenoid I0 is properly conditioned by the actuation of the relay 2'! after a predetermined interval of operation of the engine during which the switch I9 is opened if the engine is operating normally. Also, as will be apparent, if the oil pressure is not established when the engine is first started, the switch I9 is not opened and hence after the predetermined interval controlled by the time-delay switch 39, 40 the relay coil 21 is energized to move the contact elements 3|, 32 and 33 from the position shown in the drawing and the solenoid will be energized to discontinue the operation of the engine before injury to the engine occurs. Furthermore, the foregoing manner of operation permits the engine to operate for a brief period of time even though the conditions exist for calling the safety device into operation, so that for example if a vehicle operated by an engine provided withv the safety device should be stopped by the operation of the safety device in a position to obstruct trailic on a railroad track or in other hazardous or undesirable position the engine may be temporarily restarted and operated briefly sufficiently to move the vehicle to another position.

It will therefore be perceive d that me present invention"provides'asafety device of the character under consideration which in no way depends for its'operativeness upon the manual closing of a switcliwhich must first be opened in order for the safety device to be temporarily thrown out of operation in order to permit the engine to start. The safety device is thus entirely automatic in operation, and" assures the stopping of the engine promptly after starting, for example, if the oil pressure fails to develop, and the prompt stopping of the engine whenever thereafter by reason of a drop in oilpressure or an increase in'temperature a dangerous condition arises. The automatic provision thus introduced is relatively simple and compact in structure,

adding little to the complexity or bulk of the installation, while it is simple, efficient and certain in operation. It may also be readily installed for cooperation with engine controlling means already in use.

The automatic device thus provided can be made responsive to any change in pressure or temperature from which actuation is desired, those hereinbefore referred to being taken as typical only, and the solenoid or other electromagnetic control can be applied to any suitable controlling member whose operation will stop the engine, the solenoid valve, solenoid operated rack on an injection pump, etc., being taken as typical only.

While the embodiment of the invention diagrammaticallyillustrated on the drawing has been described with considerable particularity, it is to be expressly understood that the invention is not restricted thereto, as the invention can receive a variety of expressions, as will now be apparent to those skilled in the art, while changes may be made in details of circuit arrangement, mechanical and electrical elements employed, etc., without departing from the spirit of this invention. Reference is therefore to be had to the appended claims for a definition of said invention.

What is claimed is:

1. An electrically operable control device comprising a control circuit including a condition responsive switch movable between controlling positions, a normally open second switch in series circuit with the first said switch and movable to closed position for conditioning said control circuit for a controlling operation, a relay having a coil and an armature operable for closing said second switch upon energization of said coil, a normally open third switch in series circuit with said coil, and means operably associated with said third switch for effecting time delayed movement thereof to closed position, said last means including operating means connected in parallel circuit with said third switch for initiating said time delayed movement and causing energization of said coil upon expiration of a predetermined period.

2. An electrically operable control device as claimed in claim 1 wherein a normally open fourth switch is connected in circuit with said coil and is operable by said armature for maintaining said coil energized independently of the posiiton of said third switch.

3. An electrically operable control device as claimed in claim 2 wherein said parallel circuit includes a normally closed fifth switch in series with said operating means and being operable by said armature to open said parallel circuit upon energization of said coil.

7 4. An electrically operable control-device claimed in c1aim 3 wherein said means operably associated withsaid third. switch includes a bimetallic element, said operating means comprising aheater coil for said element. THOMAS J MOODY.

REFERENCES CITED Thefollowing references are of record in the file of this patent:

Number N v e Pogue Aug. 13, 193-5 Jones- June 13, 1939 Schirokauer -1 Aug. 6,1940 Reavis Dec. 28, 1943 Bartholy -1 Jan. 25,1944 Alexander Apr; 17, 1945 Ball Nov. 9, 1948 Ritchie Jan. 16, 1951 FOREIGN PATENTS Q Country Date Australia A 1, 1940 

